May 15 (GMM) Nelson Piquet risks dropping out of formula one if he cannot up his game, Renault's sporting boss has admitted.

The 22-year-old made his grand prix debut with the French squad in March, and over the first five races of 2008 he has failed to score any of Renault's nine points or outqualify his teammate Fernando Alonso.

Renault's sporting manager Steve Nielsen agrees with those pundits who believe the Brazilian youngster needs to start turning in some good drives.

"He needs to start having more good bits than the bad bits, and he needs to start doing that as soon as he can," he confirmed.

"Formula one is a business, it's a very cutthroat business, and if people don't deliver, they go the obvious way," Nielsen added.

Piquet himself, who dropped out in the 'Q1' section of qualifying in Turkey, admits that it is taking him some time to learn the ropes at the pinnacle of racing.

"Hopefully race to race I am going to improve myself and get more comfortable with everything and we'll get there. The team are very supportive, they are trying to help me as much as I need so I have nothing to complain about," he is quoted as saying by Reuters.

Piquet is scheduled to take over Renault's single car at the Paul Ricard test on Thursday and Friday, even though the weather forecast is predicting possible rain.